Drill Pipe With Increased Drill Pipe Body Wall Thickness And Outside Diameter

ABSTRACT

A tubular member for a drill pipe comprising an elongated tubular body with a first end and a second end, the first and second ends including, respectively, a box tool joint section and a pin tool joint segment, the box tool joint segment being connected to the tubular body with at least a weld neck, wherein the nominal outer diameter of the tubular member is greater than the nominal pipe body outer diameter specified under American Petroleum Institute standard API Specification 5DP for a basis tubular member, and the nominal outer diameter of the tubular member is equal to or less than the weld neck diameter limitation specified under API Specification 5DP for a basis tubular member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority pursuant to 35 U.S.C. 119(a) to U.S. Provisional Patent Application No. 63/265,118, filed Dec. 8, 2021, which application is incorporated herein by reference in its entirety.

FIELD OF THE DESCRIPTION

The present description relates generally to a tubular member adapted for use as a drill pipe segment. More particularly, the present description relates to a tubular member having an increased drill pipe body nominal wall thickness as a result of an increased drill pipe body outside diameter.

BACKGROUND

Standard drill pipe as used in oil and gas drilling operations is formed from a plurality of tubular members, the plurality being commonly referred to as a drill string, that are connected end to end using threaded connections. The tubular members comprise an elongated tubular body having a female threaded connecting member (or “box”) on one end and a male threaded connecting member (or “pin”) on the opposite end. The connector ends, or tool joint portions, are permanently joined to the main body portion of the tubular member, consisting of a drill pipe body with upset ends, such as by friction welding or the like.

In the process of oil and gas drilling, drill pipes are subjected to various stresses, which results in wear and a finite lifespan for the drill pipe body. In recent decades, the advancement of drilling practices has resulted in an increased share of drilling requiring the drill string to be operated in compression, resulting in the need for an improved relationship between drill pipe body stiffness and drill pipe weight, as shown by the following equation:

I=(π÷64)(D ⁴ −d ⁴)

where:

I=moment of inertia

D=drill pipe body outside diameter

d=drill pipe body inside diameter

The compressive forces mentioned above may result in buckling of one or more tubular members and, consequently, in excessive wear of those segments of the drill pipe as well as additional frictional resistance to rotating or advancing the drill string ahead. This is illustrated by the Dawson-Paslay equation (1984) as found in Standard DS-1 Volume 2: Drill Stem Design and Operation (Fourth Edition):

F _(c)=2[(EIwK _(B) sin θ)÷r]^(1/2)

where:

F_(c)=critical buckling load

E=Young's Modulus

I=moment of inertia

w=weight of pipe in air

K_(B)=buoyancy factor

θ=hole inclination

r=radius difference between hole and tool joint

Various solutions have been proposed to address the consequences of increased stresses mentioned above. In one instance, it has been proposed to increase the wall thickness of the drill pipe body at one or more discrete sections along its length. Such “wear pads”, while effective, serve to improve the wear characteristics of only certain, predicted sections along the length of the drill pipe body. Another solution that has been proposed is to increase the wall thickness along the entire length of the drill pipe body by maintaining the outside diameter unchanged but reducing the inside diameter, such as shown in FIG. 1B. While improving the stiffness characteristics of the tubular member, the reduced inside diameter restricts the flow rate of fluids there-through. As known in the art, both of the above solutions result in the drill string being provided with added material and, therefore, added drill string weight which may prove difficult to compressive drilling operations due to the minimal improvement in stiffness to counteract weight-induced frictional resistance. While such added weight may be useful for certain drilling operations, it may fail to address the stress and wear problems discussed above with the drill pipe body.

Although it may be assumed that another option for increasing wall thickness of a drill pipe body would be to increase the outside diameter with or without reducing the drill pipe body inside diameter, this is generally not feasible beyond a certain threshold owing to predetermined size constraints presented by drill pipe handling equipment. In this regard, sizes of drill pipe tubular members are generally dictated across the industry by the standard set by the American Petroleum Institute under “API Specification 5DP: Specification for Drill Pipe” (the entire contents of which incorporated herein as if set forth in its entirety), Tables A.1 and C.1 of which specifies the dimensions of drill pipe that may be used in the industry. This standard is also recited in ISO 11961:2008. As known in the art, drill pipe handling apparatus and devices are generally designed specifically to meet these and several additional API standards. Thus, drill pipe handling equipment that is designed for a particular drill pipe body outside diameter may be rendered useless for certain tubular members having increased body outside diameters.

Examples of attempts at providing increased outer diameter drill pipe segments are discussed in U.S. Pat. No. 9,222,314 and U.S. RE39,869.

There is a need for a drill pipe tubular member having desired stiffness characteristics while allowing for standard drill pipe handling and other equipment to be used.

SUMMARY OF THE DESCRIPTION

In one aspect, there is provided a drill pipe tubular member having a specified outside diameter that has improved stiffness characteristics over standard drill pipe tubular members.

In one aspect, there is provided a tubular member for a drill pipe comprising an elongated tubular body with first and second ends, the first and second ends including, respectively, a box tool joint section and a pin tool joint segment, the box tool joint segment being connected to the tubular body with at least a weld neck, wherein:

-   -   the outside diameter of the drill pipe body is greater than the         nominal pipe outer diameter specified under American Petroleum         Institute standard API Specification 5DP; and,     -   the inner diameter of the tubular member is equal to, greater         than, or less than the nominal pipe body inside diameter         specified under American Petroleum Institute standard API         Specification 5DP.

In another aspect, there is provided a tubular member for a drill pipe comprising an elongated tubular body with first and second ends, the first and second ends including, respectively, a box tool joint section and a pin tool joint segment, the box tool joint segment being connected to the tubular body with at least a weld neck, wherein:

-   -   the nominal outer diameter of the tubular member is greater than         the nominal pipe body outer diameter specified under American         Petroleum Institute standard API Specification 5DP for a basis         tubular member; and,     -   the nominal outer diameter of the tubular member is equal to or         less than the weld neck diameter limitation specified under API         Specification 5DP for a basis tubular member.

These and other objects, features, and advantages of the present invention will become readily apparent upon a review of the following detailed description of the invention, in view of the drawings and appended claims.

BRIEF DESCRIPTION OF THE FIGURES

The features of certain embodiments will become more apparent in the following detailed description in which reference is made to the appended figures. The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations and are not intended to limit the scope of the appended claims. In the drawings:

FIG. 1A illustrates an end view of a known pipe, such as an API Specification 5DP drill pipe, showing the pipe body outside diameter and the wall thickness.

FIG. 1B illustrates an end view of a known API Specification 5DP drill pipe modified by reducing its internal diameter.

FIG. 1C illustrates an end view of a known API Specification 5DP drill pipe modified according to the present description.

FIG. 2 is side view of a tubular member according to an aspect of the description.

FIG. 3 is a side cross-sectional view of the tubular member of FIG. 2 .

DETAILED DESCRIPTION

The terms “comprise”, “comprises”, “comprised” or “comprising” may be used in the present description. As used herein (including the specification and/or the claims), these terms are to be interpreted as open-ended terms and as specifying the presence of the stated features, integers, steps or components, but not as precluding the presence of one or more other feature, integer, step, component or a group thereof as would be apparent to persons having ordinary skill in the relevant art. Thus, the term “comprising” as used in this specification means “consisting at least in part of”. When interpreting statements in this specification that include that term, the features, prefaced by that term in each statement, all need to be present but other features can also be present. Related terms such as “comprise” and “comprised” are to be interpreted in the same manner.

The phrase “consisting essentially of” or “consists essentially of” will be understood as generally closed terms, with the exception of allowing inclusion of additional items, materials, components, steps, or elements, that do not materially affect the basic and novel characteristics or function of the item(s) used in connection therewith. When using an open-ended term, such as “comprising” or “including”, it will be understood that direct support should be afforded also to “consisting essentially of” language as well as “consisting of” language as if stated explicitly and vice versa. In essence, use of one of these terms in the specification provides support for all of the others.

The term “and/or” can mean “and” or “or”.

Unless stated otherwise herein, the articles “a” and “the”, when used to identify an element, are not intended to constitute a limitation of just one and will, instead, be understood to mean “at least one” or “one or more”.

Furthermore, it is understood that this description is not limited to the particular methodology, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to limit the scope of the claims.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention pertains. It should be understood that any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the example embodiments.

FIG. 1A illustrates a known drill pipe, such as an API Specification 5DP drill pipe, showing the inside and outside diameters of the pipe body as well as its wall thickness. FIG. 1B illustrates a known method of increasing the pipe body wall thickness but reducing its inner diameter. FIG. 1C illustrates an aspect of the present description wherein a drill pipe, such as an API Specification 5DP drill pipe, is modified by increasing the drill pipe body outside diameter. In one aspect, the inside diameter of the drill pipe body is maintained unchanged from the API Specification. However, in other aspects, the inside diameter may be increased or decreased. In FIGS. 1A to 1C, the broken lines illustrate the differences in diameters.

FIGS. 2 and 3 illustrates a typical tubular member used for forming a drill string. As known in the art, the tubular member 10 comprises an elongated body having a female, or “box” end 12 and a male, or “pin” end 14. A tubular main body portion 16, which includes end upsets and the “drill pipe body” or “pipe body” referenced often in this document, extends between the box and pin ends. The box end 12 is provided with an internal thread 18 while the pin end 14 is provided with an external thread 20. The two threaded sections are complementary, whereby each tubular member 10 may be joined to an adjacent tubular member by forming a threaded connection between adjacent box and pin sections. As mentioned above, the box and pin ends, 12 and 14, are also referred to as tool joint portions. The tubular member 10 generally has a total length of roughly 30 feet to roughly 45 feet.

The main body portion 16 of the tubular member 10 comprises an inner surface 22 having an inside diameter.

As known in the art, the box 12 and pin 14, or tool joint portions, are typically welded or otherwise affixed to the tubular main body portion 16. As also known in the art, and as illustrated in FIGS. 2 and 3 , the tool joint portions, 12 and 14, typically have larger outside diameters than the main body portion 16. The outside diameter of the box portion 12 may be the same or different as the outer diameter of the pin portion 14. The box tool joint portion 12 is connected to a first end of the main body portion 16 through a first tapered shoulder 24 and a first weld neck 26. Similarly, the pin tool joint portion 14 may be connected to a second end of the main body portion 16 through a second tapered shoulder 28 and a second weld neck 30.

The present description aims to address the deficiencies in known drill string tubular members by providing a tubular member, such as shown at 10 in FIGS. 2 and 3 , with a main body 16, upset ends excluded, having an increased outside diameter based on standard tubular sizing, but within strict limitations so as to allow drill pipe handling and other equipment associated with the standard tubular design to be used. For example, according to the present description, a tubular member is provided based on 4.500 inch standard drill pipe body outside diameter, as prescribed under API Specification 5DP or ISO 11961:2008, wherein the drill pipe body outside diameter is increased beyond 4.500 inch with or without changing the drill pipe body inside diameter thereof. As discussed above, and as would be understood by persons skilled in the art, this modification for the purpose of increasing drill pipe body wall thickness results in improved stiffness in comparison to decreasing the inside diameter without changing the outer diameter. In the result, the tubular member is less prone to buckling and other effects caused by axial compressive forces being applied to the drill string.

The present description also aims to enable drilling operators to continue using equipment for a given standard drill pipe body outside diameter even with the modified outside diameter discussed above. In this respect, the API Specification 5DP specifies the final maximum outer diameter of the first weld neck 26, located adjacent the box portion 12, as well as the associated maximum outer diameter of the main body portion 16. As also known in the art, drilling equipment, such as the elevator and other tubular handling apparatus, are designed based on the diameter specifications listed in the API Specification 5DP and, more particularly, on the diameter of the first weld neck 26. For example, for drilling a 6¾″ hole, a drill pipe having a main body 16 with a nominal outside diameter of 4.500 inch would commonly be used and, accordingly the API Specification 5DP specifies that the outer diameter of the first weld neck 26 must not exceed 4.688 inch outside diameter in order for the pipe segments to fit with the elevator used on the drilling rig. The tolerances specified in API Specification 5DP Table A.2 will be applied, except when a more restrictive tolerance is necessary.

Thus, according to an aspect of the present description, the minimum outer diameter of the main body 16 of a given tubular member 10 would be the nominal diameter, specified under API Specification 5DP, plus 0.001 inch. In addition, the upper limit of the nominal outside diameter of the main body 16 of the tubular member 10 would be the maximum drill pipe weld neck outside diameter specified in the API Specification 5DP associated with the relevant “basis” drill pipe body outside diameter. This range of outside diameter provides the added stiffness for the drill pipe while allowing the pipe to be used with standard drilling equipment.

Additionally, a new method of defining bounds of used drill pipe body class is enabled with an increased drill pipe body outside dimeter but a drill pipe body inside diameter equal to the drill pipe body inside diameter of the basis drill pipe (FIG. 1C). It is the intention of the inventors that this method, described herein, is utilized. To continue using the example of API Specification 5DP nominal drill pipe body, i.e., the basis pipe body outside diameter 4.500 inch, the standard wall thickness for said pipe body inside diameter will be 0.337 inch. The premium class pipe body minimum wall thickness will be 0.270 inch. The inventors would propose, for example, a drill pipe body nominal outside diameter of 4.563 inch, resulting in a drill pipe body wall thickness of 0.368 inch and the same premium class drill pipe body minimum wall thickness as the basis drill pipe body, which is 0.270 inch wall thickness.

Applying the above criteria, the present description provides the diameter limitations as indicated in Table 1.

TABLE 1 Tubular Member Size Parameters Tubular size designation (nominal drill pipe body Maximum weld neck Minimum drill Maximum drill outside diameter, in inch) outside diameter (inch) pipe body pipe body (per API Specification (per API Specification nominal outside nominal outside 5DP) 5DP) diameter (inch) diameter (inch) 2⅜ 2.563 2.376 2.563 (2.375) 2⅞ 3.188 2.876 3.188 (2.875) 3½ 3.875 3.501 3.875 (3.500) 4 4.188 4.001 4.188 (4.000) 4½ 4.688 4.501 4.688 (4.500) 5 5.125 5.001 5.125 (5.000) 5½ 5.688 5.501 5.688 (5.500) 6⅝ 6.938 6.626 6.938 (6.625)

The last two columns in Table 1 define the nominal outside diameter range (in terms of minimum and maximum nominal outside diameter values) of the drill pipe body according to the present description. Thus, for example, in the present description, a nominal 4.500 inch API Specification 5DP basis drill pipe body outside diameter would have a nominal drill pipe body outside diameter ranging from 4.501 inch to 4.688 inch according to the present description. The tolerances specified in API Specification 5DP Table A.2 will be applied, except when a more restrictive tolerance is necessary.

Although the above description includes reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art. Any examples provided herein are included solely for the purpose of illustration and are not intended to be limiting in any way. Any drawings provided herein are solely for the purpose of illustrating various aspects of the description and are not intended to be drawn to scale or to be limiting in any way. The scope of the description should not be limited by the preferred embodiments set forth in the above description but should be given the broadest interpretation consistent with the present specification as a whole. The disclosures of all prior art recited herein are incorporated herein by reference in their entirety.

REFERENCE NUMERALS

-   10 Tubular member -   12 Box end -   14 Pin end -   16 Main body -   18 Internal thread -   20 External thread -   22 Inner surface -   26 First weld neck -   28 Second tapered shoulder -   30 Second weld neck 

What is claimed is:
 1. A tubular member for a drill pipe comprising an elongated tubular body with first and second ends, the first and second ends including, respectively, a box tool joint section and a pin tool joint segment, the box tool joint segment being connected to the tubular body with at least a weld neck, wherein: the nominal outer diameter of the tubular member is greater than the nominal pipe body outer diameter specified under American Petroleum Institute standard API Specification 5DP for a basis tubular member; and, the nominal outer diameter of the tubular member is equal to or less than the weld neck diameter limitation specified under API Specification 5DP for a basis tubular member.
 2. The tubular member of claim 1, wherein the basis tubular member is a drill pipe with 2⅜ inch drill pipe body outside diameter, and the nominal outside diameter of the tubular body of the tubular member is within the range 2.376 inches and 2.563 inches.
 3. The tubular member of claim 1, wherein the basis tubular member is a drill pipe with 2⅞ inch drill pipe body outside diameter, and the nominal outside diameter of the tubular body of the tubular member is within the range 2.876 inches and 3.188 inches.
 4. The tubular member of claim 1, wherein the basis tubular member is a drill pipe with 3½ inch drill pipe body outside diameter, and the nominal outside diameter of the tubular body of the tubular member is within the range 3.501 inches and 3.875 inches.
 5. The tubular member of claim 1, wherein the basis tubular member is a drill pipe with 4 inch drill pipe body outside diameter, and the nominal outside diameter of the tubular body of the tubular member is within the range 4.001 and 4.188 inches.
 6. The tubular member of claim 1, wherein the basis tubular member is a drill pipe with 4½ inch drill pipe body outside diameter, and the nominal drill pipe body outside diameter is within the range 4.501 inches and 4.688 inches.
 7. The tubular member of claim 1, wherein the basis tubular member is a drill pipe with 5 inch drill pipe body outside diameter, and the nominal outside diameter of the tubular body of the tubular member is within the range 5.001 inches and 5.125 inches.
 8. The tubular member of claim 1, wherein the basis tubular member is a drill pipe with 5½ inch drill pipe body outside diameter, and the nominal outside diameter of the tubular body of the tubular member is within the range 5.501 inches and 5.688 inches.
 9. The tubular member of claim 1, wherein the basis tubular member is a drill pipe with 6⅝ inch drill pipe body outside diameter, and the nominal outside diameter of the tubular body of the tubular member is within the range 6.626 inches and 6.938 inches. 